Ok, this is strange. We have a 5-month-old foster who came in yesterday. She had a large bump on top of her head that was soft to the touch. The person who had her before us said that it came and went once, and that they thought it was a hematoma from rough play with two older dogs. It was large and firm last night, and this morning it is completely gone. She has a vet appointment tomorrow morning, I just wondered if anyone has seen anything like this, and if you know if it could be anything more serious. Furthermore, if the "coming-and-going" nature of the bump sounds like anything with which you are familiar. Thanks for your help!